A San Francisco sheriff’s deputy who left his service pistol unsecured in a parked car over the weekend, allowing a thief to break in and take it, is no longer employed by the department, officials said Tuesday.

The unidentified deputy had been with the agency for less than a year and was still on probation when he reported the burglary in Potrero Hill Sunday, said Eileen Hirst, chief of staff for the Sheriff's Department.

Sheriff Vicki Hennessy said Monday that the deputy had violated department policy in leaving his 9mm Glock 17 handgun in the trunk of a rental car. Department policy states that if a deputy must leave a gun in a vehicle, it must be stored in a metal lock box fixed to the interior and out of view.

The burglary happened during an epidemic of vehicle break-ins in San Francisco. Through the end of July, 17,970 car burglaries had been reported across the city, a 28 percent jump from the same period last year.

Guns stolen from law-enforcement vehicles have been used in a number of shootings in recent years in the Bay Area, including the killing of Kate Steinle on San Francisco’s Pier 14 in July 2015. That case prompted city and state lawmakers to tighten the rules for securing firearms in vehicles, but the problem persists.

A revolver taken from a San Francisco police officer’s personal vehicle last month was used three days later in the killing of 23-year-old Abel Enrique Esquivel Jr. in the Mission District. Three young men, who allegedly went on a spree of street robberies with the gun, have been charged with murder.

The actions of the city officer who owned the gun, which was recovered, are under investigation.